As from the year 2012, new rules for tennis games for young participants are being internationally introduced. Thus, in connection with training and playing, the young participants will be divided into different age groups, 5-8 years, 8-10 years, 9-10 years and those above the age of 11. These new rules imply, for example, that the different age groups will play under different conditions with regard to: the size of the racket, the hardness and hence speed of the ball, the size of the court and the height of the net.
In these contexts, the arrangement of the height of the net for different age groups is a factor that is difficult or laborious. At one and the same court, it may occur that young participants of various age groups and also senior players alternate with each other and have different playing-times. This may require a complicated adjustment of the height of the net which for the moment is to be adapted to the relevant category of players. One way of arranging this is to replace a net for the last playing category of players with a net adapted to the players that will use the court during the next period of time. Another way of achieving the height adjustment is to quite simply vary the height of the upper net edge above the ground by moving the whole net upwards or downwards by using existing hoisting and tensioning devices which are arranged at the posts which stretch the net at the ends thereof. A disadvantage of varying the height of the net in the last-mentioned way is that a traditional net in the raised position may let through balls below the net, since the net does not reach down to the ground in the raised position.
U.S. Pat. No. 4,852,876 discloses a solution for arranging a net with a vertically adjustable (i.e. raisable and lowerable) upper edge in a net for a tennis court. According to this solution, an upper auxiliary net is arranged. This auxiliary net has an upper longitudinal edge and a lower longitudinal edge, where the upper and lower longitudinal edges are fixed to auxiliary posts which may be hoisted, in the vertical direction, along fixed posts for the net at the two opposite sides of the court. Between the fixed poles, a lower fixed net is placed and stretched. The upper auxiliary net is arranged such that, when hoisted upwards or downwards, it runs parallel to the fixed net along one side thereof. By hoisting it upwards or downwards, the upper auxiliary net may be arranged with the upper longitudinal edge to a desired total height for the whole net. A disadvantage of this arrangement is that balls that are captured by the upper auxiliary net have a tendency to fall down between the upper auxiliary net and the lower fixed net, where these two parts of the net overlap.
No international standard regulating the arrangement of a vertically adjustable net has as yet been adopted.